Conventional processing systems may operate in a mode specified during configuration with an instruction set optimized to process data of a specific size (e.g., 32-bit mode or 64-bit mode). However, to change the mode of operation, conventional processing systems typically must be stopped (e.g., brought to a quiescent state). Placing a processing system in a quiescent state is inefficient as processing must be halted. Accordingly, improved methods for changing a processing system mode of operation are desired.